This invention relates to indicators and in particular analog visual indicators which indicate using a liquid medium.
Analog indicators have existed since time immemorial. The hour glass, for example, uses sand or water which, influenced by the weight of gravity, moves from one reservoir to another by passing through a small aperture therebetween. Another example of an ancient analog indicator is the “Clepsydra”, as illustrated in “Horloges Anciennes” by Richard Miihe and Horand M. Vogel, French Edition, Office du Livre, Fribourg, 1978, page 9.
Referring to FIG. 1, U.S. Pat. No. 3,783,598 describes an instrument 1 having a movement 2, a drive shaft 3, cams 4, pistons 5, fluid filled capillaries 6 and a relief chamber 7. Such instrument indicates time. Referring to FIG. 2, timepieces exist that use a liquid pumped into cavities 8 below which are semi-transparent stones 9, to create a digital representation of time.
These prior devices are cumbersome, requiring significant or dedicated space for indicating the value, lack accuracy or only give the impression of a fluid indicator.
What is needed is a visual indicator that provides a quickly read indication of a measured value, such as speed, temperature, instantaneous time, the time passed, or time remaining before a certain event.